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Title:	Effect of TiO2 nanoparticles addition on photophysical properties of a novel white emitting ternary conjugated polymer blend thin film
Authors:	Albati Sameer Nabeel Hassan (P90631)
Supervisor:	Mohammad Hafizuddin Hj. Jumali, Assoc. Prof. Dr.
Keywords:	Conjugated polymers Polymers Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	25-May-2021
Description:	The key issue with the optoelectronic devices based on the conjugated polymers is the low luminescence efficiency. This issue stems from the poor exciton creation inside the active layer due to the limitations of electron transitions and charge mobility in the conjugated polymers. The objective of this study was to improve the photoluminescence property of ternary polymer blend thin films through enhancement of excitons creation. In addition, the effect of TiO2 nanoparticles additions on the photoluminescence of the ternary polymer blend thin films has been investigated with the ultimate aim to produce white emission. The three conjugated polymers used in this study are poly(9,9-dioctylfluorene-2,7-diyl) (PFO), poly 9,9-dioctylfluorene-alt-benzothiadiazole (F8BT) and poly(2-methoxy-5(2-ethylhexyl)-1,4-phenylenevinylene (MEH-PPV). This study began by analyzing the absorption and emission relationships between the polymers in the binary blends before progressing ternary blends. The solution blending method was used to prepare different polymers and nanocomposite blends. In all blends, the PFO content was fixed at 15 mg/ml. To produce thin films, all the blends were deposited onto glass substrates and ITO coated glass substrates using the spin-coating technique. The deposition parameters were fixed at 2000 rpm with a spinning duration of 30 s. The optical properties of all thin films were studied by recording absorption and emission spectra using UV-Vis and PL spectrophotometer, respectively. All binary polymer blends showed efficient non-radiative energy transfer. All energy transfer parameters pointed that the dipole-dipole interaction (Förster resonance energy transfer) was the energy transfer mechanism in the blends. To achieve the desired white emission from the ternary blend, a content control strategy was applied. For this work, optimum PFO/MEH-PPV blend with minor quenching and efficient energy transfer was selected. The additions of different wt.% of F8BT causing the PFO emission successively quenched, indicating the creation of exciplex. Interestingly, the addition of TiO2 nanoparticles up to 10 wt.% inhibited the exciplex creation and intensified the white emission. Besides, TiO2 nanoparticles promoted the creation of exciton in the donor polymer PFO by a mechanism known as the electron trapping effect. Unfortunately, at higher TiO2 nanoparticles content, the emission consistently reduced due to severe agglomerations. The current density and turn-on voltage of the ternary blend thin films showed a strong dependency on the content and distribution of the TiO2 nanoparticles. This work successfully produced a novel white emission nanocomposite ternary polymer blend layer, namely, PFO/0.3wt.øBT/0.5wt.%MEH-PPV/10wt.%TiO2.,Ph.D,The key issue with the optoelectronic devices based on the conjugated polymers is the low luminescence efficiency. This issue stems from the poor exciton creation inside the active layer due to the limitations of electron transitions and charge mobility in the conjugated polymers. The objective of this study was to improve the photoluminescence property of ternary polymer blend thin films through enhancement of excitons creation. In addition, the effect of TiO2 nanoparticles additions on the photoluminescence of the ternary polymer blend thin films has been investigated with the ultimate aim to produce white emission. The three conjugated polymers used in this study are poly(9,9-dioctylfluorene-2,7-diyl) (PFO), poly 9,9-dioctylfluorene-alt-benzothiadiazole (F8BT) and poly(2-methoxy-5(2-ethylhexyl)-1,4-phenylenevinylene (MEH-PPV). This study began by analyzing the absorption and emission relationships between the polymers in the binary blends before progressing ternary blends. The solution blending method was used to prepare different polymers and nanocomposite blends. In all blends, the PFO content was fixed at 15 mg/ml. To produce thin films, all the blends were deposited onto glass substrates and ITO coated glass substrates using the spin-coating technique. The deposition parameters were fixed at 2000 rpm with a spinning duration of 30 s. The optical properties of all thin films were studied by recording absorption and emission spectra using UV-Vis and PL spectrophotometer, respectively. All binary polymer blends showed efficient non-radiative energy transfer. All energy transfer parameters pointed that the dipole-dipole interaction (Förster resonance energy transfer) was the energy transfer mechanism in the blends. To achieve the desired white emission from the ternary blend, a content control strategy was applied. For this work, optimum PFO/MEH-PPV blend with minor quenching and efficient energy transfer was selected. The additions of different wt.% of F8BT causing the PFO emission successively quenched, indicating the creation of exciplex. Interestingly, the addition of TiO2 nanoparticles up to 10 wt.% inhibited the exciplex creation and intensified the white emission. Besides, TiO2 nanoparticles promoted the creation of exciton in the donor polymer PFO by a mechanism known as the electron trapping effect. Unfortunately, at higher TiO2 nanoparticles content, the emission consistently reduced due to severe agglomerations. The current density and turn-on voltage of the ternary blend thin films showed a strong dependency on the content and distribution of the TiO2 nanoparticles. This work successfully produced a novel white emission nanocomposite ternary polymer blend layer, namely, PFO/0.3wt.%F8BT/0.5wt.%MEH-PPV/10wt.%TiO2.
Pages:	133
Call Number:	QD382.C66A433 2021 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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